In Australia, a large number of level crossings in rural areas have no protection from a potential collision between a car and a train other than passive warning signs and the available visibility. Warrants have been established to provide guidance on the size of the `sight triangle' required at these sites to enable drivers to see an approaching train in sufficient time to stop or to proceed safely over the crossing. However the size of the triangle is significant for most typical combinations of car and train approach speeds and in many cases obstructions occur within the sight triangle which limit the effective visibility. This paper proposes a method of classifying crossings with inadequate visibility so that these may be placed in priority order for budgeted improvement works. A system is proposed to quickly identify the relative degree of hazard. The paper suggests that sight triangle dimensions incorporate several safety factors that allow the triangle to be grade according to rational steps in the safety factors used. This method could be used to grade sites depending on relative visibility hazard and also to highlight sites which are intrinsically hazardous. (A)
Abstract